Deep-SeaResearchI51(2004)1145–1157 Flowpredictioninupwellingdeepseawater—theperpetual saltfountain X.R.Zhang a, *,S.Maruyama a ,S.Sakai a ,K.Tsubaki a ,M.Behnia b a Institute of Fluid Science, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan b Office of the Dean of Graduate Studies, The University of Sydney, NSW 2006, Australia Received20May2003;receivedinrevisedform21October2003;accepted30March2004 Abstract Amodelhasbeendevelopedtopredicttheinducedflowandheattransferinupwellingdeepwaterusingtheperpetual saltfountain.Theupwellingflowoftheseawaterisinducedbythebuoyancyforce,whichisdrivenbysimultaneous temperatureandsalinitydifferences.Bothlaminarandturbulentflowmodelsareconsideredinconjunctionwiththe analysis of upwelling velocity, temperature and density distributions. The theoretical solutions for laminar natural convectioninverticalductsareusedtoverifythecomputationalmodelandvalidatethenumericalcode.Acomparison ofnumericalpredictionandexperimentaldataobtainedintheupperoceanintheregionofMarianaTrench(Pacific Ocean)ispresentedandthereasonableagreementbetweenthenumericalpredictionbytheturbulentmodelandthe experimentalresultsisencouraging.Futureresearchshouldaimtodeterminethecompletenatureoftheflowandheat transferinupwellingdeepwaterusingtheperpetualsaltfountain. r 2004ElsevierLtd.Allrightsreserved. Keywords: Deepwater;Upwelling;Perpetualsaltfountain;Masstransport;Tracer;PacificOcean 1. Introduction In 1956, Stommel et al. (1956) proposed ‘‘the perpetual salt fountain’’. In many tropical and subtropicaloceanregions,thewarmsurfacelayers haveahighersalinitythanthatofthecolderdeep water.Ifalongtubewereloweredfromthesurface to a depth of low-salinity water, and the deep seawater were slowly pumped up to the surface through the tube, and then the pump were disconnected, the seawater would continue to flow, by itself. This remarkable phenomenon occursbecausetheslowmotionthroughthetube allows the water inside it to attain the same temperatureasthesurroundingwater.Itssalinity, andhencedensity,isthereforelessthanthatofits surroundings outside the tube, and hence the entirecolumnofwaterinsidethetubeisbuoyant withrespecttothefluidoutsideatthesamelevel. After the proposal was put forward, however, onlyasimplelaboratoryexperimentdemonstrated theprinciple,andHowardandStommelfailedto ARTICLE IN PRESS *Correspondingauthor.Tel./fax:+81-22-217-5244. E-mail address: xrzhang@pixy.ifs.tohoku.ac.jp (X.R.Zhang). 0967-0637/$-seefrontmatter r 2004ElsevierLtd.Allrightsreserved. doi:10.1016/j.dsr.2004.03.010